Deleted Game logic layout by accident
You have 2 menu below that looks like icons with 2 arrows. In your screenshot  there are icons like "cube" (which is view port where you can see your objects, scene and anything you are working on) and "clock".

If you don't use the clock just click on it and choose Logic Editor, and then after all set up you can save this view as  "game logic" - just rename it from "default". So as we see even we accidentally delete any of menus we can add it by yourself